To be GOVERNED is to be watched, inspected, spied upon, directed, law-driven, numbered, regulated, enrolled, indoctrinated, preached at, controlled, checked, estimated, valued, censured, commanded, by creatures who have neither the right nor the wisdom nor the virtue to do so. Proudhon

Lack of energy may have nothing to do with time management. It may be a medical problem. I was suffering from almost continuous fatigue early this year and taking a multi-vitamin tablet daily sorted it out virtually immediately.

Apart from that, I have always said that the best source of energy is to be completely on top of your work.

Based on past writings he means something deeper. You can only achieve so much. If you add more than that to your list, you will inevitably and repeatedly fall behind. It's not about overdue tasks only, but it's about what work you take on to begin with. Too much and you are doomed to fail.